(1) Field of the Invention
The invention relates to a lithium secondary cell array of a cylindrical design with a winding mandrel and a winding package, which contains foil-like, coated strips and contacting strips that form the electric cell structure consisting of the anode, cathode and separator, and having external electrical connecting means, these comprising pole caps in accordance with claim 1.
(2) Description of Related Art
DE 696 36 796 T2 discloses a cylindrical secondary battery comprising pole caps already known, whereby the contact is established such that the respective foil of the winding is guided to the outside like a strip. In this case, either a plurality of such strips has to be handled, which can lead to mechanical problems such as compression or material breaks, or there is a limitation to a few strips which are led out from the foil winding, but which reduces the current carrying capacity.
DE 699 00 105 T2 already discloses a secondary battery with non-aqueous electrolytes in the form of a winding arrangement. There, an elongated positive and negative electrode with a separator is laminated in such a manner that the positive electrode forms an outer layer.
In DE 699 13 570 T2, the lithium secondary cell shown there is designed as a rolled cylinder. Furthermore there are connector assemblies which are contacted by a plurality of electrode contact pins, so that the electric power generated by the accommodated electrode unit can be supplied to an external device. In addition, a cover is provided for the entire assembly with a gas vent plug. However, the electrode contact pins used for contacting, which ensure the desired contacting at certain intervals within the winding, only allow the use of a small part of the material cross-section for the actual current transport. This means that the power is limited during both charging and discharging of a corresponding lithium secondary cell.
The generic DE 10 2007 000 428 A1 assumes a winding mandrel of a lithium ion cell. There is a trilaminate of anode, cathode and separator on the winding mandrel. Furthermore, there are so-called pole plugs, whereby the trilaminate is wound around the winding mandrel to produce the desired winding and whereby the pole caps are inserted into the ends of the winding mandrel. The diameter of the head of the pole caps in accordance with DE 10 2007 000 428 A1 is smaller than the diameter of the winding. In one embodiment a washer is fitted before fastening the pole cap to the winding mandrel and this is then located between the winding and pole cap. This washer has a diameter which can be up to the maximum diameter of the winding and is made of a material of the corresponding poles, e.g. copper for the anode side or aluminium for the cathode side. In a further embodiment the washer can be realised as a star, cross or spoke. This should enable a shakeproof fixation of the pole contact. The contacting of the washer with the foil winding is effected through welding, which is a very complicated technological step.
With respect to the prior art in terms of secondary batteries with non-aqueous electrolytes, reference is made to DE 698 29 544 T2, and with respect to a method to recover materials from lithium cells to DE 694 20 438 T2.
Cooling ventilation is provided in the stackable energy store based on lithium polymer cells in accordance with DE 10 2007 032 520 A1. The cooling air is passed through the device by a tube-like winding mandrel. Pole caps in this are designed as threaded tubes that are screwed into the lower and upper part of the winding mandrel. The pole caps perform the cooling ventilation.